[RFC] checkpatch.pl: warn if an adding line introduce spaces before tabs.

[Alberto Panizzo <maramaopercheseimorto@gmail.com>]

This apply to the linux-next tree.

It is a useful thing to warn.

Signed-off-by: Alberto Panizzo <maramaopercheseimorto@gmail.com>
---
 scripts/checkpatch.pl |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index bc4114f..ab18a11 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -1411,6 +1411,12 @@ sub process {
 			ERROR("code indent should use tabs where possible\n" . $herevet);
 		}
 
+# check for space before tabs.
+		if ($rawline =~ /^\+/ && $rawline =~ / \t/) {
+			my $herevet = "$here\n" . cat_vet($rawline) . "\n";
+			WARN("please, no space before tabs\n" . $herevet);
+		}
+
 # check we are in a valid C source file if not then ignore this hunk
 		next if ($realfile !~ /\.(h|c)$/);
 
-- 
1.6.3.3